Synergetic-modified porous Co2SiO4 conductive network with ZIF-8 derived carbon and reduced graphene oxide for high-rate lithium-ion battery anode

Abstract

Aiming at the key problems such as low conductivity, volume expansion rate and poor rate performance faced by high-capacity silicon-based anode, a three-dimensional porous Co2SiO4/rGO/ZIFC conductive network is designed and prepared by synergistic modifying Co2SiO4 with reduced graphene oxide (rGO) and ZIF-8 derived carbon (ZIFC). The internal rGO as a lamellar template, supporting substrate and conductive bridge accelerates the transfer of electrons, while the external reasonable coating of ZIF-8 derived carbon greatly maintains the overall structure of the material and supplies fields for lithium-ion diffusion. The obtained porous structure can not only lead to excellent ion diffusion rate and promote the electrochemical interface reaction, but also relieve volume expansion of the material during the cycling, thus heightening the electrochemical performance. The obtained Co2SiO4/rGO/ZIFC electrode offers an outstanding specific capacity of 1295 mA h g−1 at 0.2 A g−1 and 650 mA h g−1 even at a high electric current density of 5 A g−1. The pseudocapacitance ratio of the Co2SiO4/rGO/ZIFC anode at a scan rate of 0.8 mV s−1 is as high as 91%, verifying its excellent lithium ion kinetics and promising rate performance.